Circuit interrupter



3' Sheets-Sheet l .1. SANDIN CIRCUIT INTERRUPTER FiledDec. 30, 1937 May30, 1939.

'INVENTOR Jerome .Sand/n 4 BY WW AT'TORNE WITNESSES;

May 30, 1939. J. SANDIN CIRCUIT INTERRUPTER Filed Dec. 30, 1937. 3Sheets-Sheet 2 L1llll llll T ATTORNE INVENTOR Jerome Sand/n Fig. 3..

May 30, 1939. J. SANDIN QIRCUIT INTERRUPTER Filed Dec. 30, 1937 3Sheets-Sheet 3 INVENTOR Jerome Sand/r) a ATTORNE Patelited May30,1939

UNITED STATES PATENT OFFICE Am Dumber SI, 1931, Sub! No. 182,484

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Disposed between the wall members 50 are a plurality of deionizingplates 52, 54 and 56 of conducting material. The opposed inner surfacesof the wall members 50 are provided with slots or channels as shown at58 and 60 of Figs. 6 and '7 for receiving a portion of the side edges ofthe plates. I

The uppermost slot in the wall members 50 has a somewhat greater widththan the remaining slots so as to accommodate the side edges of both theplate 52 of conducting material and an additional plate 62 of insulatingmaterial. The wall members 50 are held in clamping engagement with theentire assemblage of plates by means of rivets 64 passing transverselythrough the wall members so as. to unite plates and wall members in aunitary structure. Each wall member 50 is provided with spacedindentations or recesses extending from the outer surface inwardly, asshown at-66, so as to provide an intermediate shoulder portion 66 whichhas a vertical bore Ill therethrough for receiving a mounting screw 12.The mounting screw 12 is adapt-ed to be screwed into the base 20,thereby securely holding the arc extinguishing structure 48 as a unit inproper position with respect to the contacts 24 and 26. This method ofmounting the arc extinguishing structure facilitates the removal andreplacement thereof for purposes of inspection and repair of either theare extinguishing structure or the breaker contacts.

The are extinguishing plates 52, 54 and 56 have a V-shaped slot 'l3formed in one end thereof, as shown in Figs. 3, 5, 6 and 7. As shownmore clearly in Figs. 4 and 5, the arc extinguishing plates are moreclosely spaced at their slotted ends and are arranged with their slotsin superimposed relation so as to form an aligned are receiving groovein which the moving contact 26 is adapted to be moved for establishingan arc. Inasmuch as the arc extinguishing plates converge towards theslotted ends, the plates 56 .are shorter than the plates 54 in order' tomaintain suillcient spacing between the ends of the plates to preventinsulation failure. The are extinguishing plates 52, 54 and 56 arepreferably of magnetic material such as iron or other ferrous materialso that when the arc is drawn between the contacts 24 and 26, themagnetic reaction set up by the plates 52, 54 and 56 will move the arctowards the apex of the slots and into the plates. The initial movementof the arc is effected chiefly by the plates 52 and 54 inasmuch as theseplates have the side edges along their V-shaped slot extending onopposite The opposed surfaces of the side wall members 50 adjacent theslots in the arc extinguishing plates taper inwardly in the direction ofarc movement so as to provide a convergent entrance passage for the arc.The narrow constricted portion between the opposed wall members 50extends a considerable distance along the are receiving slots and againwidens in the direction of arc movement as clearly shown in Figs. 1, 3,5, 6 and '7. This tapering entrance portion, as provided by the sidewalls 50, serves to contract the are so as to facilitate entry thereofinto the arc extinguishing plates 54 and 56. I have discovered, however,that if the arc is permitted to strike to the side edges of the slots inplates 54 during the arc drawing process, considerable difllculty isexperienced in effecting arc movement into the deionizing plates. Inorder to overcome this difficulty, the portions of the plates 54 oneither side of the path of movement of the moving contact 26 are deeplyembedded or recessed in the grooves 60, as shown in Fig. 6. Theuppermost plate 52, however, is not recessed within the taperingportions of the wall members 50 as more clearly shown in Fig. 7, sincethis plate member serves as the upper arc terminal during arc movementtowards the end of the slots.

In some instances, particularly in the extinction of heavy current arcswhich travel with relatively high velocities due to the strong magneticreaction propelling the same, the short arcs between theplates 52, 54and 56 may move beyond the ends thereof. In order to prevent the shortarcs from moving beyond the plates and restriking into a single arc, Ihave provided two transversely disposed barriers 14 of insulatingmaterial, at medial points along the arc path. The barriers 14 haveportions thereof extending between two adjacent deionizing plates sothat in the event certain of the short arcs succeed in passing throughthe plates and tend to restrike as a single arc,'there will be a suddenlengthening of the arc at the barriers which causes the arc to beextinguished. The barriers 14 also serve to cool the hot gases emanatingfrom between the deionizing plates and in this respect assist in thesuppression of the arc and flame caused by the hot gases.

Although the barriers I4, as particularly shown in-Fig. 4, have acertain cooling effect upon the discharged gases from between thedeionizing plates, I have found that in certain instances it may bedesirable to provide further means for cooling the gas and arresting theflame produced during circuit interruption. In Fig. 8, I have shown amodified structure of insulating material which combines a perforatedbaflle with the barriers previously described. In this particularinstance, the barrier portions 16 have united integrally therewith abaflle plate 16 provided with openings therethrough. The baflle plate 18extends transversely between the wall members 50 in the direct path ofthe gas discharge from the spaces between the deionizing plates. Thus asthe gas emerges from these spaces, it strikes the barrier portion 16 andthe bafile plate 18 and is forced to flow through the openings 80.During such movement through the openings in the baflie plate 18, thegases are sufllciently cooled to arrestany flame which might appear atthe edges of the deionizing plates. Additional baflle means ofinsulating material are provided, as

cooling and suppressing the hot gases at the top and bottom of the arcextinguishing structure.

Figs. 10, 11 and 12 show a further modification of combined barrier andbaille plate arrangement for preventing the issuance of an are beyondthe end of the arc extinguishing structure. The arrangement shown inthese figures is somewhat similar to that shown in Figs. 8 and 9 exceptthat an additional barrier plate 82 is provided. The baflle plate 82 isspaced from the bafile plate 18 by two transversely extending ribs 84which ribs are adapted to seat in aligned grooves provided transverselyof the baflle plate I8. The ends of the ribs 84 extend beyond the sidesof the plate 82 and are preferably embedded in suitable notches 86provided in the side wall members 50. The width of the plate 82 is alsosomewhat narrower than the distance between the side wall members 50 inorder to provide escapement for the gas passing through the apertures 80in the baffle plate 18. This structure is believed to be somewhat moreemcient than that shown in Figs. 8 and 9, in that it provides acircuitous path of greater length to be traversed by the escaping gasand consequently cools the gas to a greater degree, thereby insuring acomplete arresting of flame.

Although I have shown and described specific arc extinguishingstructures and the use thereof in a particular breaker structure, it isto be understood that the same is for the purpose of illustration andthat changes and modifications may be made by those skilled in the artwithout departing from the spirit and scope of the appended claims.

I claim as my invention:

1. An arc extinguishing device for circuit interrupters comprising meansof insulating material defining two opposed surfaces of an arc passage,said means of insulating material having a plurality of spaced groovesdisposed along said opposed surfaces, a plurality of plates ofconducting material disposed transversely between said opposed surfacesand having their side edges supported within said grooves, each of saidplates having an arc receiving slot in one end thereof, a plurality ofsaid plates having a part of their slot defining portions completelyrecessed in said, means of insulating material to prevent an areestablished adjacent said recessed portions from striking thereto. I

2. An arc extinguishing device for circuit interrupters comprising apair of spaced wall members of' insulating material, said wall membershaving a portion of their opposed surfaces adjacent one end taperingtowards each other to provide a converging arc receiving passage, aplurality of spaced metallic plates disposed between said wall members,said plates having a V-shaped slot in one end thereof and considerableportions thereof defining the sides of said slots completely embedded insaid tapering portions of said wall members for preventing an arc fromstriking to said embedded portions.

3. An arc extinguishing device for circuit interrupters comprising aplurality of spaced plates of conducting material, said plates having aV-shaped slot in one end thereof to form an aligned are receiving groovea pair of unitary support members of insulating material disposed onopposite sides of said plates for defining the side walls of an arcpassage in which an arc is adapted to play, the opposed surfaces of saidsupport members adjacent the sides of said slots tapering inwardly toprovide an entrance portion for said arc passage which graduallydecreases in width in a direction toward the closed end of said grooveand in which an arc is adapted to be established, and recesses along thetapered surfaces of said support members for receiving the edges of aplurality of said plates.

4. In a circuit interrupter, a pair of spaced support members ofinsulating material, said support members having a plurality of spacedgrooves along their opposed inner surfaces, a plurality of plates ofmagnetic material disposed between said support members with their sideedges resting in said grooves, means for holding said support members inengagement with said plates, each of said plates having a V-shaped slotextending inwardly from one end thereof to form an aligned are receivingchannel, a plurality of said plates having portions adjacent either sideof their slots extending beyond the remaining plates, and means forestablishing an arc between said support members in a directionsubstantially normal to said extended portions of said plates, saidextended portions of said plates being of substantially less width thanthe depth of the grooves in said support members in which said portionsare disposed to prevent said arc from striking to said extended portionswhen it is established and during its movement by the magnetic reactionset up by said plates toward the end of said are receiving channel.

5. An arc extinguishing device for circuit interrupters comprising aplurality of spaced metallic plates, each of said plates having an arereceiving slot in one end thereof, a pair of wall members of insulatingmaterial between which said metallic plates are disposed, the inneropposed surfaces of said wall members being provided with a plurality oflongitudinally extending grooves for receiving the side edges of saidmetallic plates,

and means for holding said wall members in engagement with said plates,each wall member having a pair of recesses extending inwardly from theouter surface thereof, said recesses in each wall member being elongatedin a direction parallel to the outer surface thereof and disposed inspaced longitudinal alignment to provide an intermediate portion, saidintermediate portion of each wall member having an opening therethroughin alignment with said recesses for the reception of securing means formounting said device upon a suitable support.

6. In an arc extingin'shing device, a pairof spaced support members ofinsulating material, a plurality of metallic plates disposed in spacedrelation between said support members, each of said metallic plateshaving a slot therein for receiving an arc to be extinguished, means formoving an are into said plates to form a plurality of short seriallyrelated arcs therebetween, plate means of insulating material supportedbetween said support members and having a portion thereof disposedbetween two adjacent metallic plates to prevent the short arcs frommoving beyond the ends of said metallic plates and reuniting into asingle arc, and means associated with said plate means to assist thelatter in cooling the arc gases discharged from the spaces between themetallic plates.

7. In a circuitinterrupter, a plurality of plates of conductingmaterial, said plates having an are receiving slot in one end thereof, apair of support members of insulating material disposed on in the slotsof said plates, means for moving said arc into said plates to form aplurality of short serially related arcs, a plurality of plates ofinsulating material disposed between said support members, each of saidplates of insulating material having at least a portion thereofinterposed between two adjacent plates of conducting material, saidplates of insulating material preventing the reformation of saidplurality of serially related arcs into a single arc across the ends ofsaid plates of condutllng material, and means associated with saidplates of insulating material disposed adjacent the ends ofsaid.conducting plate to provide a circuitous path for the gasdischarged from the spaces between said conducting plates for coolingsaid gas.

8. In a circuit interrupter, a stack of plates of ferrous material, saidstack of plates having an aligned are receiving slot in one end thereof,a

pair of insulating wall members disposed on opposite sides of said stackof plates for holding the plates in spaced relation, means forestablishing an arc 'within said slot, said are being moved into saidplates by the magnetic reaction set up therein by the arc and split intoa plurality of short serially related arcs playing between said plates,and a barrier member of insulating material disposed between said wallmembers adjacent the ends of said plates, said barrier member having atleast a portion thereof extending between two adjacent plates to preventthe short arcs from restriking as a single are along the ends of saidplates and a baiiie portion extending transversely of the spaces betweenthe ends of said plates, said baflle portion providing a circuitous pathfor the gas discharged from said spaces for cooling said gas.

JEROME SANDIN.

